Method of accurately shaping printing plates and apparatus therefor



H. A. W. WOOD 1,933,885

Original Filed March 1925 NQV. 7, 19330 METHOD OF ACCURATELY SHAPING PRINTING PLATES AND APPARATUS THEREFOR Patented Nov. 7, 1933 UNITED STATES METHOD OF ACCURATELY SHAPING PRINTING PLATES AND THEREFOR APPARATUS Henry A. Wise Wood, New York, N. Y., assignor to Wood Newspaper Machinery Corporation, New York, N. Y., a corporation of Virginia Application March 17,

1925, Serial No.-16,216

Renewed May 11, 1932 12 Claims.

This invention relates to the fitting of printing plates for the cylinders or the like on which they are to be placed in a printing press.

The principal object of the invention isto provide for following up the shaving and plate holding operations by the cooling of the plate in such a way as to continue to hold the plate in the position and condition in which it was shaved so that the plate will set in that condition and so that all cooling strains and displacements will be removed from the plate while held firmly under pressure. Thus the plate comes out in a true accurate shape, ready to apply to the plate holding part of the printing machine ready to print. Another object of the invention is to provide for forcing the low spots on the plate against an accurately shaped surface so that all printing parts upon the surface of the plate will be of the same height. The invention also involves the provision of special means for accomplishing the latter result which will out through at theback of the high spots so as not to put undue pressure upon the metal at that point and a shaving blade movable just in the rear of this means to shave the plate while in close contact with the backing up surface. I provide a water-cooled saddle following the shaving blade and holding the plate in its final dimension by' the application of pressure thereto. All this is done preferably while the plate is in ahot and comparatively soft state so that it can be forced back against the backing up surface. This saddle is hung eccentrically so that it can be adjusted very easily to hold the plate snugly between the two surfaces during cooling.

Other objects and advantages of the inventio will appear hereinafter.

Reference is to be had to the accompanying drawing, in which Fig. l is a cross sectional view of a shaving arch for a semi-cylindrical stereotype printing plate showing a preferred form of this invention applied thereto;

Fig. 2 is a sectional View on the radial line 22 of Fig. 1 showing the shape of the concave side of the plate and the means for pushing the plate back against the arch;

Fig. 3 is a fragmentary view similar to Fig. 1 showing a modification;

- Fig. 4 is a view similar to Fig. 2 of this modification; and

Fig. 5 is a sectional view similar to Fig. 1 showing one way of applying this invention to a flat plate.

I have shown the invention as applied to a shaving arch 1 of the usual type carrying within it a plate 2 placed therein in the usual way and held in position so as to be shaped and shaved to the exact curvature of the cylinder on which it is to be placed. For this purpose I'cast the plate 2 with a series of grooves 12 on the concave side arranged around it circumferentially. I place also on the cutting'shaft lO a bracket 11 on which are a series of rollers '3 -mounted' loosely on a shaft 13 held by the bracket. These rollers are free to turn fand, as shown .more clearly in Fig. 2, have conical sides so as to provide a sharp edge which will engage in the shallow cylindrical bottoms of the grooves 12 duringthe rotation of the shaft 10.

As shown in Figs. 3 and 4, instead of rotary rollers 3 I can provide a stationary knife 4 having a series of teeth therealong having a similar shape to the edges of the roller 3. These operate in substantially the same way, engaging the bottoms of the grooves. It will be noticed that these knives are not arranged so that their forward edges Will cut into the plate but they have convex V-shaped edges that press against.

it like'the rollers.

In either case, the rollers or knives of this element press against the bottoms of the grooves 12 and force the plate into the arch so that high spots and low spots will be forced back against the properlyshapedsurface of the concave arch. In any ,plate there are likely to be points where different thicknesses occur. When a thin place is over the rollers or knives, the latter will force that back into the arch so that the type surface will engage the arch at that point, which it never would if this operation were not performed upon. it. When thick spots come into engagement with the rollers orknives they will cut or wedge themselves into the backs of the grooves slightly at those points, Distortion and bruising of the'metal is avoided because these wedge. shaped surfaces can wedge themselves further into the bottoms of the grooves 12 whichdoes no harm and-performs no further function.

On the bracket 11 I mount the usual shaving blade 5 which shaves the back of the plate, irrespective of the grooves, to the proper thickness.

This is placed as close to the rollers 3 or knives eccentric and capable of turning to move the rear end of the saddle out and in very slightly for adjustment. The saddle has a place inside for cooling water and water is circulated through it as it is through the arch itself. This saddle is intended to bear on the inner surface of the plate sufficiently to force it firmly against the arch.

The cooling saddle follows up the holding and shaving means and it not only cools and sets the metal but it continues to hold the plate accurately against the shaping surface of the arch while the plate is so cooled. This permits all cooling strains in the plate to be removed while the plate is under pressure. Thus when the plate comes out of the machine its surface is true and accurate and it is ready to be applied to the printing cylinder for printing. It will not warp after this complete operation.

All these operations are performed while the plate is hot and comparatively soft so that it is'capable of being Worked upon by these different instrumentalities without the expenditure of any greatamount of power. It will be seen that the plate is first forced back against the arch and any low printing spot on the plate by this forcing operation is bodily moved toward the concave side of the arch while the thick portions are left where they are and if necessary cut through a little on the back. The plate is held here while it is being shaved before the saddle is brought around and the plate further cooled.

In the form shown in Fig. 5 I have illustrated the application of this principle to a fiat plate where it performs exactly the same functions. In this case either the plate or the shaving apparatus can reciprocate as may be desired. Here we have a support 21 for a shaft 22 and a series of rollers 23. Back of them oncthe same support is a shaving blade 25 and back of that a saddle 26 supported as before on a pair of transverse studs not shown. When reciprocation takes place between the plate and the mecha-.

nism, the same operation is performed as in the other four figures.

Although I have illustrated and described only three forms of theinvention I am aware of the fact that other modifications can be made therein without departing from the scope of the invention as expressed in the claims. Therefore I do not wish to be limited to any or all of the forms illustrated but what I do claimflis:

l. The method of shaping printing plates which consists in'applying pressure to the back of the plate at a series of points along it to force all low printing areas of the plate against a surface on'the front side and plowing through the backs of the thick parts of the plate at the same points so that the entire front printing surface of the plate will conform accurately and uniformly to the desired shape, holding the plate firmly against such surface progressively across the plate and shaving the'back of the plate while so held.

2. The method of shaping printing plates which consists in applying pressure to the back of the plate at a series of points along it to force low printing areas of the plate against a surface on the front side, plowing through the backs of the thick parts of the plate so that the en? ire front printing surface of the plate will conform to the desired shapes, shaving the back of the plate, and then applying a cooling means progressively along the rear surface of the plate to cool the plate effectively.

3. The method of shaping a printing plate which consists in progressively pressing the plate from the rear side against a surface of the desired shape while the plate is in a' hot and comparatively soft state, then immediately shaving the back of the plate, passing a cooling element of the shape of the rear of the plate along the rear surface of the plate, and progressively holding the plate in the proper shape during cooling.

4. The method of shaping and cooling a printingplate which consists in pressing the plate from the rear side against a surface of the desired shape, immediately shaving the back of the plate while the plate is so pressed against that surface, and passing a cooling element along the rear surface of the plate behind the shaving blade.

5. Inan apparatus for shaping a stereotype plate having a series of parallel tapered grooves in the rear surface, the combination with means for holdinglthe plate, said means having a surface of the shape which is desired for the printing surface of the plate, a bracket movable under the plate, a series of cutters extending across the plate mounted on said bracket and having tapering edges engaging in said grooves'in the rear of the p ate to maintain the shape of the'grooves, and a shaving blade mounted on the bracket behind said cutters.

6. In an apparatus for shaping and cooling a stereotype plate having a' series of parallel grooves in the rear surface, the combination with means for holding the plate, said means having a surface of the shape which is desired for the printing surface of the plate, a bracket movable under the plate, a series of cutters extending across the plate mounted on said bracket and having tapering edges engaging in said grooves in the rear of the plate, a shaving blade'mounted on the bracket behind-said cutters, and a cooling saddle movable with the bracket and having a shape the same as the desired shape of the plate, said cooling saddle having a water receiving space i is for cooling purposes and being adjustable to per ing tapering ends engaging the rear of the plate,

a shaving blade mounted on the bracket behind said cutters, and a cooling saddle movable with the bracket and having a shape the same as the desired shape of the plate, said cooling saddle having a water receiving space for cooling purposes and being adjustable to permit of its pressing against the plate. a

8. In an apparatus for shaping the back of a stereotype plate, the combination with means for holding the plate against a surface shaped to conform to the plate, of a saddle movable relatively to theplate holding means and having a smooth surface adapted to hold the rear surface of the plate down to the desired dimension in thickness, said saddle having a water receiving space for cooling purposes and being adjustable toward and from the plate.

, 9. The method of shaping printing plates which consists in applying pressure to the back of the plate to force the plate against a surface on the front side, plowing through the backs of the thick parts of the plate, shaving the back of the plate, and then applying a cooling means progressively along the rear surface of the plate.

10, The method of shaping, shaving, and cooling a printing plate which consists in forcing the printing surface of the plate against a true shaping surface, shaving the back of the plate while the face thereof is held in contact with the shaping surface and thereafter passing a cooling medium over the back of the plate, to cool and set the plate, and holding the plate by the cooling medium while cooling in firm contact with the shaping surface, so that the plate will have taken its set before the cooling medium is withdrawn.

11. In an apparatus for shaping, shaving, and setting a curved stereotype printing plate, the combination of a concave arch against the surface of which the type surface of the plate is adapted tobe clamped, a longitudinal shaft at the center of said arch, a shaving blade fixed to the shaft to be rotated therewith, and a cooling saddle having a convex surface of substantially the same radius as that of the interior surface of said plate carried by said shaft behind the shaving blade to hold the plate against the concave shaft to be rotated therewith, a cooling saddle having a convex surface of substantially the same radius as that of the interior surface of said plate carriedby said shaft behindthe shaving blade to hold the plate against the concave surface of the arch and simultaneously cool and set the plate while so held, said cooling saddle being pivotally mounted near its forward end, and means near its rear end for adjusting that end of the saddle'toward and from the plate. 7

. HENRY A. WISEWOOD. 

